Scanning apparatus and method of making same



May 2, 1933. P. GARNER SCANNING APPARATUS" AND METHOD OF MAKING SAME Filed Sept. 10, 1929 n r wa w :wG m J d I fl Patented May 2, 1933 umrEofsrA-TES PATENTOFFICEF LLOYD r. GARNER, or ciIIoAeo, ILLrnoIs, ASSIGNOR T wEsrEBN TELEV SION coma, or CHICAGO, ILLInoIs, A oonroanrron or DELAWARE SCANN ING APPARATUS AND METHOD OF MAKING SAME Application filed September 10, 1929. Serial No. 391,656.

My invention relates to scanning apparatus for television and has particular reference to disc and drum scanners of the small aperture type. My invention also relates to a method of making the same.

In scanning apparatus such as discs and drums of the small aperture type it is essential that the apertures be small and accurately positioned and in order to obtain the best optical results the material immediately surrounding the aperture should be as thin as possible. As the disc or drum is made smaller or the number of apertures increased, the diameter of the apertures decreases which necessitates greater accuracy in locating the apertures. It has been difficultto form these small apertures economically, due to the fact that if they are punched or drilled, to prevent breakage of the punch or drill, the thickness of the disc should be less than the diameter of the aperture to be formed, and a disc of this thickness Will not hold its shape when rotated at the speed necessary for television work.

It is an object of my invention to provide a scanning disc of relatively thick material, having apertures defined by relatively thin material.

A further object of my invention is to provide a rotating scanning device in which the apertures are formed in material too thin to hold its shape when rotated, and having means for holding it in shape.

A further object of my invention is to provide a scanning disc which is sturdy in construction, economical to manufacture and which will lend itself to quantity production and still make possible the use of very small apertures.

A further object of my invention is to provide a scanning device having apertures which will give improved optical results.

A further object of my invention is to provide a convenient method for punching small apertures in a relatively thick sheet of material.

A further object of my invention is to provide a method of manufacture which shall require no radical development in the way of apparatus for practising the method and which shall insure uniform production with no more skill on the part of the operator than is required in ordinary punching 'operations, and a method which shall be not only simple as to acts performed and inexpensive as to the apparatus required, but which shall lend itself to quantity production.

My invention will be better understood from the following description taken inconnection with the accompanying drawing in which:

I Fig. 1 is a perspective of a quarter segment of the preferred form of my invention:

Fig. 2 is a fragmentary elevation of a modification I F ig. 3 is a section along line 33 of Fig. 2: and

Fig. 4 is a fragmentary section of another modification. w

Figure 1 illustrates the preferred form of my invention which comprises a disc 10 of any suitable material such as aluminum, provided with depressions 11 Which the apertures 12 are located. The depressions 11 are formed preferably by punching and are of such depth that the bottoms 13 of the depressions 11 are ofa thickness less than the diameter of the apertures 12 which are to be formed. After the depressions 11 are formed with their centers approximately coinciding with the centers of the apertures 12 to be formed the apertures 12 are accurately positioned and due to the reduced thickness of the disc 10 at these points the apertures 12 may be punched without any great danger of breaking the punch, as is the case when the thickness of the disc is greater than the diameter of the hole to be punched. This method and construction readily lends itself to quantity production, using existing apparatus. It will be understood, however, that my invention is not limited to forming the depressions 11 and the apertures 12 by punching but may be formed in any suitable manner, such as by drilling or otherwise' In practising my invention; to form in a disc of relatively thick material, having apertures surrounded by relatively thin material, I reduce the thickness of limited portions of the material and then form the apertures in such portions of reduced thickness.

As shown in Figure 2, the disc 10 is provided with relatively large holes 14 which are covered over with thin material 15 in which the apertures 12 are formed. In making this form of my invention, the holes 14 are formed in the disc 10 which may be of relatively thick material. Small sections 15 of relatively thin material are then placed over the holes 14 and secured to the disc 10 in any suitable manner, as by spot welding. After the sections 15 have been secured in place the small apertures 12 are formed therein, preferably by punching.

Figure 3 illustrates another form which my invention may take, which comprises a disc '16 of relatively thin material positioned between two relatively thick discs 17 and 18, all three of which are secured together by any suitable means, such as spot welding. The thin disc 16 is provided with small apertures 12 which coincide with the holes 19 in the thick discs 17 and 18. In order that the apertures 12 may be easily formed by punching, the thin disc 16 is preferabl of a thickness less than the diameter o the apertures 12 and where very small apertures are desired the thin disc 16 will be too thin to hold its shape when being rotated. To strengthen the thin disc 16 so that it will hold its shape, the thick discs 17 and 18 are provided. In constructing this disc, the large holes 19 are formed in the thick discs 17 and 18 approximately in the locations where it is desired to form the analyzing apertures. The three discs 17, 16 and 18 are secured together as shown, preferably by spot welding, and the small apertures 12 are then accurately formed in the thin disc 16 by punching or otherwise.

From the above it is seen that my invention provides a scanning device in which the apertures are formed in relatively thin material, thereby approximating the ideal pin-hole lens, since the losses due to reflection and absorption of light by the side walls of the aperture are reduced to a minimum. Also, due to the thinness of the material immediately surrounding the apertures they may be punched or drilled without danger of breaking the punch or drill. Further embodiments, modifications and variations may be resorted to within the spirit of the invention as here claimed.

What I claim as new and desire to secure by Letters Patent of the United States is: 1. A rotatable scanning device comprising a thin disc having apertures therein and a disc of greater thickness than said thin disc arranged at opposite sides thereof and supporting said thin disc, each said disc of and registering with the apertures of said thin disc.

2. A scanning device com rising a body member having a plurality ofcorrespondin depressions at opposite sides thereof an having a thin portion of said body member separating said corresponding depressions, each said thin portion having an aperture extendin therethrough.

In testimony w ereof I hereunto afix my signature this 31st day of August, 1929.

LLOYD P. GARNER.

greater thickness having apertures of greater size than the apertures of said thin disc 

